Lena Dunham is struggling to come to terms with the criticism she has received after losing weight, adding that women in Hollywood just can't win.

Lena Dunham feels frustrated that some people have labelled her a "hypocrite" because of her recent weight loss.

The 30-year-old actress has been displaying a more svelte figure in recent weeks, which she credits to personal trainer Tracy Anderson encouraging her to embark on a new exercise regime in a bid to control her endometriosis pain.

Appearing on The Ellen DeGeneres Show on Wednesday (22Mar17), Lena opened up about the rude comments she has received from social media trolls since debuting her weight loss.

"It's just so crazy because I spent six years of my career being called things like 'bag of milk' on the internet, you know 'baby cow,' 'aging cow.' I just never felt self conscious about it," Lena said. "Anyone who's going to take the time to say something negative about my weight on the Internet wasn't someone I was particularly keen to impress anyway.

"(But) I was frustrated by it because it really was evidence that as a woman in Hollywood, you just can't win."

Lena was labelled a "hypocrite" by some, who felt her weight loss was going against her former message to be confident in yourself regardless of size.

But the Girls star insists people need to realise that bodies change over the years - and that's not something she needs to apologise for.

"I had this experience of my body changing and suddenly I had all these people being like, 'you're a hypocrite, I thought you were body positive. I thought you were a person who embraced bodies of all sizes,' and I'm like I do, I just also understand that bodies change, we live a long time, things happen'," she smiled.

Lena recently showed off her flexibility in a cover shoot for Nylon magazine, in which she strikes a series of impressive yoga poses. And when Ellen addressed the recent shoot, Lena decided to prove her flexibility once again by recreating one of the poses which involved placing her leg behind her head.

"You can't do this in front of anyone without them thinking, she's probably pretty good at sex," Lena laughed.